Comment »Posted on Monday 15 September 2008 at 1:50 pm by Jacob Aron
In Climate Change & Environment

The cover story of the latest issue of New Scientist throws up some food for thought (sorry, bad, bad joke), and if you have a subscription to the magazine you can read the full text on their website.

The article suggests that in the average US household food consumption produces almost twice as much greenhouse gases as driving. Using “equivalent CO2 emissions”, a measure that includes other greenhouse gases along with the infamous carbon, a recent study found that 8.1 tonnes of CO2eq make up an average “food-print”, whilst a typical year’s car use emits only 4.4 tonnes of CO2eq.

Calculation of CO2eq figures is extremely complex. You have to factor in all of the energy used in getting food to your stomach, from the fuel used by tractors, to the refrigeration in supermarkets, and even the methane emitted by cows. Complicating matters further, it is difficult to translate these numbers from one region to another – because farming and food distribution methods differ widely in different countries, a steak eaten the US doesn’t necessarily have the same CO2eq footprint as one eaten in the UK.

You might think that eating local could help you cut down on emissions. Supermarkets are already trying to implement “food miles” labelling, but a study by Christopher Weber, an environmental policy researcher at Carnegie Mellon University in Pennsylvania, found that transportation of food makes up only 11% of the total greenhouse emissions. Most of the energy goes in to food production – a whopping 83%. The title of this posts reflects that fact: a bowl of cereal will set you back 1224 grams of CO2eq, roughly the same as a 6 km drive in a typical gas-guzzling SUV.

It’s not even the cereal which is to blame here – it’s the milk. Cows have a huge carbon footprint, which gives weight to the argument of Gidon Eshel and Pamela Martin of the University of Chicago, who calculated that switching to a vegetarian diet could cut your emissions by almost 1.5 tonnes of CO2eq. Some of my friends have already gone veggie for this exact reason, but I’m not quite ready to give up sausages just yet.

One solution is in vitro meat. Essentially, animal cells are grown in a lab to form edible meat, without having to feed and care for an actual animal. The concept horrifies many people, but I personally have no problem with it (as long as the meat still tastes good!), and People for the Ethical Treatment of Animals are offering a $1 million dollar prize reward to anyone who can bring in vitro meat to market.

Unfortunately for PETA, it seems that treating your chickens badly actually lowers their carbon footprint. Next time you’re in the supermarket, you might find yourself wondering whether to side with Jamie Oliver or Al Gore, since organic chicken require 10% more energy than their battery-farmed cousins because they live longer and are allowed to move about more.

What then should your average consumer do to reduce their carbon food-print? I’d recommended the introduction of vegetarian meals into your diet, without going full-on meat free. Vegetable curries are always a good option, and I’m quite partial to a mushroom risotto. Just stay away from the cardboard-like “meat substitutes” that vegetarians seem to sustain themselves on – I think I’d rather have global warming!


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